As a travel distance measurement device that is mounted to a vehicle (railroad train) and measures the travel distance of the vehicle by using a radio wave, there is provided, for example, a device that uses a Doppler frequency, as shown in patent reference 1. The device shown in this patent reference 1 emits a radio wave as a transmission signal toward a ground surface (rail track surface) first, and acquires a Doppler signal component by mixing a reflection signal which is a reflected wave reflected from the ground surface with the transmission signal. The device then analyzes the Doppler frequency of the signal and calculates and integrates the traveling speed of the vehicle, thereby acquiring the travel distance of the vehicle.